XIII 



PHYLUM CHORDATA 



145 



and, after giving off branches to the pseudobranch, passes into the 

 cranial cavity and joins the internal carotid of the opposite side. 



The dorsal aorta runs backwards throughout the length of the 

 body cavity, giving off" 

 numerous branches, 

 and is continued as 

 the caudal artery, 

 which runs in the 

 canal enclosed by the 

 inferior arches of the 

 caudal vertebrae. The 

 first pair of branches 

 are the subclavian, for 

 the supply of the 

 pectoral fins ; these 

 are given off between 

 the third and fourth 

 pairs of efferent ar- 

 teries. The next large 

 branch is the un- 

 paired cceliac (Fig. 

 772, cceL): this runs 

 in the mesentery and 

 divides into branches 

 for the supply of the 

 stomach and liver, the 

 first part of the in- 

 testine, and the pan- 

 creas. The anterior 

 mesenteric artery, also 

 median, supplies the 

 rest of the intestine 

 and gives off branches 

 to the reproductive 

 organs. The lieno- 

 gastric supplies part 

 of the stomach, the 

 spleen, and part of the 

 pancreas. The pos- 

 terior mesenteric is a 

 small vessel mainly 

 supplying the rectal 

 gland. A pair of 

 small rc'iift/. arteries 

 carry a small quantity 



of arterial blood to the kidneys, and a pair of iliac arteries, 

 likewise of small size, supply the pelvic fins. In addition to 



VOL. II L 



r.porb.v 



FIG. 774. Chiloscy Ilium. Diagrammatic representation of 

 the ventral aorta and afferent branchial arteries, and of the 

 chief veins, all. alimentary canal ; br. v.l-br. ?.5 afferent 

 branchial arteries ; caud. v. caudal vein ; dcf. e. ductus 

 Cuvieri ; lit. heart ; hep. port. v. hepatic portal vein ; hep. s. 

 hepatic sinus ; inf. jug. v. inferior jugular vein or sinus ; 

 jug. jugular vein or sinus ; lat. v. lateral vein ; liv. liver ; 

 1. can/, s. left cardinal sinus ; I. port. v. left renal portal vein 

 neph. kidney ; r. card. s. right posterior cardinal 

 r. port. v. right renal portal vein. 



sinus ; 



